> Thanks for the overwhelming quantity of answers. It looks like it might
be
>a real problem.
> I will answer to everybody in one message.
> To be more precise on my configuration:
> - The first starter relay I was using was the one sold by ACS (p/n
> 22735
on
>their catalog) for homebuilders .It started to stick lets say after 3 months
>of my initial testing ( I was already flying by that time) and was the one
>used for the initial start of the engine when it was sometime a bit
>difficult to start with a low battery.
> - The second relay was bought in France to a company called Aerostock
in Le
>bourget airport. It started sticking after 15 days of use. I am now flying
>quite often and the engine is firing very quickly and very nicely due to the
>jeff rose ignition with a fully loaded battery ( I am flying a lot).
> -I took it out and found out it a was a 24v relay. So I went back to
>Aerostock and they changed it for a 12v one. The one I got looks very much
>alike the master relay ( p/n 111-226 in ACS catalog). It started not doing
>its job after a week.
This explains it. NONE of heavy duty contactors in that package
are suited to starter contactor service . . . for a time,
RBM Controls, later White-Rogers, now Stancore built a series of
intermittant duty relays with heavier coil wires and stronger closure
forces but the way that contactor is designed internally, it just
doesn't get the contact PRESSURE that modern automotive starter
contactors enjoy.
The contactor we sell (S702-1) is of this family of devices.
> I know have two plans to attack that problem:
> 1-A friend of mine gave me a brand new ACS 22735 relay he had in his
>hangar. I might put that one on and keep the diodes that I had added on the
>previous relay ( The first relay had a diode between the coil and ground but
>not between the output and ground).
Our conactor has the arc supression diode built into the contactor
coil assembly.
> 2-I recently bought a renault truck starter relay which looks
> impressive
>(not to say massive) and very strong. I did not use it yet because I
>measured the coil resistance and found out that it was 4 ohms. This would
>mean that I would be pulling at least 3 amps through the triggering push
>button and given the size of that button this would be way too much. So I
>can decide to use it but I would have to trigger the coil of that new relay
>through another relay, maybe the previous one that could accept that 3 amp
>current easily. Is this overkill?
No, the fact that you read the low resistance is FIRST indication that
this is an intermittant duty contactor probably designed for higher
contact pressures therefore much more suited to working with starters.
Our S702-1 contactor is also a 4 ohm coil . . . The starter push-button
we recommend is heaftier than most . . . or you can rig your magnetos
to use switches and built the starter function into the switches. This
is illustrated several ways in the diagrams at:
http://www.aeroelectric.com/errata/R9Z_0400.pdf
> I would like to thank for the LED advice. It is a very good one because
I
>had already implemented that in my bird and this is what allowed me to do
>the identification of the problem.In fact , every switch has a Led that
>lights up when it is on and the information is picked up trough a wire that
>is coming from the back of the equipment the given switch is supposed to
>energise.I like that set up a lot because I have an emergency power switch
>that power a very minimum of what is needed ( to cover the alternator
>failure) and when the switch is on "alternate" the LED's give me exactly
>what is on.
Do you also have some form of automatic disabling of the alternator
in case of a failed regulator runaway? This needs to be an automatic
function that operates in tens of milliseonds. Pilot monitoring of
any instrumentation with the hope of adequately controlling a runaway
by shutting the thing off is overly optomistic and potentially expensive.
> Well, this is were I am . It is late now and I am going to bed as you
guys
>are now working.
> May be I will find out more to morrow morning with maybe a direct
> advice
>from Bill bainbridge. Just burry in mind that I am now so happy to fly that
>bird that waiting 3 or more days for a part coming from the states is too
>much. I want to fly to-morrow except if the wheather is bad (it might
>happen).
Bill is going to tell you that you need a REAL starter contactor like
his, like mine or probably like the one you just bought . . . however,
it's possible that our contactors are smaller and lighter. My S701-1
is 280 gm and fits inside a 6 x 6 x 6 cm cube. Bill's is very close
to the same dimensions.
Bob . . .
--------------------------------------------
( Knowing about a thing is different from )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
http://www.aeroelectric.com
|